There are 10 pins.
You measured 8.
Measure them all.

IF you find 5v, switch to ohms (2 clicks clockwise, omega symbol) measure the other 4 to ground.

myne wrote on 2024-10-08, 04:37:

IF you find 5v, switch to ohms (2 clicks clockwise, omega symbol) measure the other 4 to ground.

_after_ turning computer OFF. Voltage/amperes with computer on, resistance always with computer off.

Touche

>1: 0v (Far Right/'east')
>2:0v (Bottom/'south')
>3:1.5v (Far Left/'west')
>5:0v (Bottom Left/'southwest')

All those measurements are too chaotic for me to wrap my head around, which pin was which??! 😀
Only one pin at 1.5V make no sense. PS2 wouldnt work in such state, both Data and Clock need to be pulled to VCC to work.

>Will also note with my ground probe just plugged into the AT Ground pin, I was seeing .4v or so on the meter.

with other probe just in the air? shit meter or you are standing under High voltage lines/ rubbed a ton of balloons 😀 0.4mV would make sense, but not 0.4V.

Measure resistance of little SMD parts marked
- F2 (R19)
- L3
- C7
Judging by F marking and size of footprint this should be a Fuse, looks like your budget board got a 0 ohm resistor instead :] This is where both Keyboard and PS2 mouse get their power from. It might be blown, or the inductor behind it, small cap might be shorted and that blown the "fuse". All those measurements with PSU disconnected.

The odd Southwest stuff was about the keyboard din. That's sorted with the floppy bodge.

I think you're right about r19.
Looks broken.
That'll fix the kb properly.

I doubt usb comes off there.

Wait for all 10 measurements.

Also measure the voltage either side of these 2 components :

Honestly, I think my meter isn't the best, it's a cheaper on (Innova 3320) I got off Amazon some time ago in case I ever needed one, but I've never really used it. Surely a lot of the problems are me just not knowing what I'm doing. I have noticed that sometimes it takes a long time for the meter to settle in on a value, slowly counting up or down, before finally stopping, and other times it gets the value right away. Maybe that's normal though. Anyways, here's some of the checks you guys asked for.

DCV on the USB Headers

CN6/USB1 DCV to Ground (Machine On)
1: 3.72 V
2: 18.6 mV
3: 18.6 mV
4: 18.6 mV
5: 18.6 mV

CH7/DCV DCV to Ground (Machine On)
1: 3.7 V
2: 18.6mV
3: 18.6mV
4: 18.6mV
5: 18.6mV

Ohms on the USB Headers

CH6/Ohms to Ground (Machine Off)
2: 14.96 K
3: 14.86 K
4: 0.1
5: 0.1

CH7/Ohms to Ground (Machine Off)
2: 14.83 K
3: 14.97 K
4: 0.2
5: 0.2

Oh, and for all the tests above, I double checked. USB Controller and USB Keyboard Support are both enabled in BIOS.

As for the keyboard connector area, I think you might be right. No continuity across R19/F2 or C7. I am getting it across L3 & R15. Here's a close up of the area. I guess I'll just have to live with the floppy 'bodge' 😀

Ok 1 is definitely 5v. Quite low at 3.7v though. Maybe a power saving feature?
4 and 5 are ground.

Try swapping green and white on 1 of them.
Might be wired backwards?

If that doesn't work, it's probably because the voltage is too low.

MeatballB wrote on 2024-10-08, 10:08:

No continuity across R19/F2 or C7. I am getting it across L3

Great, means R19/F2 is blown. You can solder a thin wire in its place and keyboard/mouse will start working.

So, I tried swapping Green/White on the USB, and still no go. Maybe there's just not enough juice flowing through that header to work. I _did_ have it working at one point, but maybe I just got lucky.

On the plus side. "Bodge 2.0" is in effect and I jumped across R19/F2 with a small piece of copper wire and some electrical tape to hold it in place until I can get a soldering iron and AT keyboard is working. Woot! 😀

Edit: And on the plus side, this frees up the PS2 port, which is now working with a mouse 😀

Dear God that's dodgy.
No soldering iron?

For usb did you measure those 2 components I highlighted? I think that's 5v, and maybe that capacitor is bad.

Take a fool res pic of the board is you can.
The first one is too blurry to make out much detail

Ordered a soldering iron and will fix it when it comes in. Really just wanted to make sure that worked. I can't tell for sure which components you highlighted for USB, pic was small/blurry. Here's a better/higher res image of the board. Let me know if you want something in one specific area.

myne wrote on 2024-10-08, 07:40:

Also measure the voltage either side of these 2 components :

I can't tell from your picture exactly what you circled, but I assume you mean L30 and L32.

L30 is reading 3.5v on both sides. L32 is reading 18.3mV on both sides.

I think I found the culprit though. Looking on the other side of the capacitor near it, I'm reading 5v at F3, but only 3.5v at F4. I think that's another fuse between them, so maybe that's going too. Thinking I may need to solder a wire between those two pads as well.

Edit: Adding a close up pic of that area.

Sounds like you have it.
I'd suggest getting 0ohm resistors like were there.

If you have other dead things, pretty much every board has ones you can steal

myne wrote on 2024-10-09, 00:59:

Sounds like you have it.
I'd suggest getting 0ohm resistors like were there.

If you have other dead things, pretty much every board has ones you can steal

Thanks. Probably be a few days, but will loop back once I get a chance to try to deal with the trouble spots. Again, really appreciate the help from all of you.

It was quite a puzzle tbh. Kinda enjoyed the brain exercise.

Are you going to try testing usb with a bodge like the ps2?

myne wrote on 2024-10-09, 01:11:

It was quite a puzzle tbh. Kinda enjoyed the brain exercise.

Are you going to try testing usb with a bodge like the ps2?

Hmm, not sure. Where do you think I could feed 5v on that side? I don't think there's any pins or anything like I had by the AT that I can attach the floppy 5v to.

I thought you would tape a wire over f4 like you did for ps2.

But you could also jam a paperclip in the usb plug red wire while it's plugged in and use the floppy plug on that.

myne wrote on 2024-10-09, 01:22:

I thought you would tape a wire over f4 like you did for ps2.

But you could also jam a paperclip in the usb plug red wire while it's plugged in and use the floppy plug on that.

Ah, yeah, I'll give it a go, probably can't tonight though. Will let you know what happens. 😀

Yeah, just tested it. 😀 Small piece of wire temporarily held in place on those two pads brought both USB headers back to life. Guess it's time to practice/learn soldering.

Practice on a dead thing first.
Use more flux than you think you need.

When you feel moderately ready pull spare 0ohm resistors from donor.
Then dead ones from this.
Then replace.